Wobus Rating Formula

Each team's rating has a defined relation to the ratings of its
games' opponents, except for losses to much-higher-rated teams
and wins against much-lower-rated teams.
Specifically, any losing opponent with a rating more than one below
the team's rating or any winning opponent with
a rating more than one above the team's rating is not used in
the calculation.

For this description, I'll refer to the wins and losses that are
not so discounted as the "relevant wins and losses" and I'll refer
to the opponents in these games as the "relevant opponents".
If a team plays a relevant opponent two or more times, then I'm
counting it as that many opponents.

Each team's rating equals its number of relevant wins,
minus its number of relevant losses, plus the sum of the ratings
of its relevant opponents, all divided by one more than its number of
relevant opponents. Furthermore, as a group, the ratings are centered
so that the sum of all the teams' ratings is zero.

I go through repeated calculations to come up with numbers that
are as close as I can manage to these criteria.